Method for producing solid electrolytic capacitor

Abstract

There is provided a method for producing a solid electrolytic capacitor having an improved capacitance appearance ratio by forming a conductive polymer layer in a few steps. A method for producing a solid electrolytic capacitor obtained by forming solid electrolyte layer 5 and cathode 6 on dielectric layer 2 formed on anode body 1 , which is a porous body of a valve action metal, includes the step of forming precoat layer 3 by the steps of impregnating the porous body with polyacid, water washing, and drying.

1 . A method for producing a solid electrolytic capacitor, comprising the steps of:
 forming a precoat layer on a dielectric layer by the steps of impregnating with polyacid an anode body comprising a porous body of a valve action metal and having the dielectric layer formed on a surface thereof, water washing, and drying;   forming a solid electrolyte layer on the precoat layer by the steps of impregnating with and drying a conductive polymer compound-dispersed aqueous solution; and   forming a cathode.   
     
     
         2 . The method for producing a solid electrolytic capacitor according to  claim 1 , wherein the step of water washing is performed until the pH of washing water after washing is in the range of 5 to 8. 
     
     
         3 . The method for producing a solid electrolytic capacitor according to  claim 1 , wherein the polyacid is at least one selected from polysulfonic acid and polycarboxylic acid. 
     
     
         4 . The method for producing a solid electrolytic capacitor according to  claim 3 , wherein the polysulfonic acid is at least one selected from polystyrenesulfonic acid and polyester sulfonic acid. 
     
     
         5 . The method for producing a solid electrolytic capacitor according to  claim 3 , wherein the weight average molecular weight of the polysulfonic acid is less than 50,000. 
     
     
         6 . The method for producing a solid electrolytic capacitor according to  claim 1 , wherein the step of impregnating with polyacid is performed for 1 hour or more. 
     
     
         7 . The method for producing a solid electrolytic capacitor according to  claim 1 , wherein the valve action metal is at least one selected from aluminum, tantalum, niobium, titanium, and zirconium.